During processing of articles immersed in an electroplating bath, particulate materials may settle on horizontal flat and concave surfaces, referred to as shelf areas. These particles can interfere with the electroplating process and cause roughness in the deposit and visible imperfections that detract from the aesthetic qualities and/or functional qualities of the electroplated article. Also, gas generated at electrodes can accumulate on downwardly facing horizontal flat and concave surfaces. This accumulation of gas may also cause defects. Further, electrolyte solution from the electroplating bath can be carried from the bath by shelf areas of the processed article when the rack carrying the article is removed from the bath. This electrolyte drag-out is undesirable because it depletes the electrolyte in the electroplating bath and wastes process solution.
Accordingly, it is desirable to eliminate or at least minimize shelf areas of an article during electroplating of the article and during removal of the article from the electroplating bath. It is especially desirable to arrange the article in an orientation during electroplating that eliminates or at least minimizes shelf areas of the article that are normally visible during use of the article.
A relatively obvious solution to the problems associated with electroplating articles having shelf areas is to provide an electroplating rack designed to support the articles in an orientation that minimizes shelf areas, especially shelf areas that are visible during normal use of the article. However, in the case of certain articles, such as plastic wheel covers, mounting of the articles on the rack and demounting of the articles from the rack in a most preferred orientation for electroplating can be difficult and time consuming. For example, the preferred orientation of a plastic wheel cover, such as for an automobile, during electroplating is one in which the concave outwardly facing rim surfaces that are visible during normal use of a vehicle are facing downwardly to prevent particulate matter from settling on these normally visible concave surfaces and to prevent drag-out of the electrolyte during removal of the electroplating rack supporting the wheel cover. However, a cylindrical electrode is typically positioned with its axis generally aligned with the central axis of the wheel cover so that the outer cylinder walls are substantially adjacent the normally visible outwardly facing concave rim surfaces of the wheel cover to facilitate production of a uniform, imperfection-free plating on these surfaces. As a result, it is necessary to first mount the wheel cover on the electroplating rack, and then mount the electrode in the recessed hub of the wheel cover. Mounting of the wheel cover in an appropriate inverted orientation, and subsequent mounting of an electrode within the downwardly facing hub recess is difficult and requires substantially more time than mounting the wheel cover in a more conventional orientation in which the central axis of the hub is aligned horizontally, especially when a plurality of vertically closely spaced apart wheel covers are mounted together on a single rack. Similarly, the most desirable orientation for demounting wheel covers from an electroplating rack is with the central axis of the wheel cover aligned horizontally.
Therefore, the most desirable orientation for mounting articles on, and/or demounting articles from, an electroplating rack is not always the same orientation that is most desirable for electroplating the article.